Apparatus and method for heating catalyst for start-up of a compact fuel processor

ABSTRACT

The present invention specifically relates to the methods and apparatus for heating a catalyst bed for start-up and for providing heat to a catalyst bed during transient operation to maintain desired reaction temperatures. An electrical heating element may directly or indirectly heat the catalyst. The direct heating of catalyst is achieved by having direct contact of the heater element with the catalyst. Indirect heating is achieved by direct heating of a fluid, such as a process flow, which in turn flows through the catalyst, thereby transferring heat to the catalyst. Additionally, indirect heating may be achieved by placing the heating element within a sheath that is then either in direct contact with the catalyst or fluid that flows through the catalyst. By these means, catalyst of many forms may employ this catalyst heater including pellets, extrudates, spheres, and monoliths. The catalyst heater in accordance with this invention can be made of any resistive wire, cartridges, or rods that may be coupled to a power source to provide the energy to produce the heat.

BACKGROUND OF THE INVENTION

[0001] Fuel cells provide electricity from chemical oxidation-reductionreactions and possess significant advantages over other forms of powergeneration in terms of cleanliness and efficiency. Typically, fuel cellsemploy hydrogen as the fuel and oxygen as the oxidizing agent. The powergeneration is proportional to the consumption rate of the reactants.

[0002] A significant disadvantage which inhibits the wider use of fuelcells is the lack of a widespread hydrogen infrastructure. Hydrogen hasa relatively low volumetric energy density and is more difficult tostore and transport than the hydrocarbon fuels currently used in mostpower generation systems. One way to overcome this difficulty is the useof reformers to convert the hydrocarbons to a hydrogen rich gas streamwhich can be used as a feed for fuel cells.

[0003] Hydrocarbon-based fuels, such as natural gas, LPG, gasoline, anddiesel, require conversion processes to be used as fuel sources for mostfuel cells. Current art uses multi-step processes combining an initialconversion process with several clean-up processes. The initial processis most often steam reforming (SR), autothermal reforming (ATR),catalytic partial oxidation (CPOX), or non-catalytic partial oxidation(POX). The clean-up processes are usually comprised of a combination ofdesulfurization, high temperature water-gas shift, low temperaturewater-gas shift, selective CO oxidation, or selective CO methanation.Alternative processes include hydrogen selective membrane reactors andfilters.

[0004] Despite the above work, there remains a need for a simple unitfor converting a hydrocarbon fuel to a hydrogen rich gas stream for usewith a fuel cell. A practical obstacle facing any solution to thisproblem is the need to start-up catalyst beds and maintain desiredreaction temperatures during transient operation. The present inventionaddresses this need.

SUMMARY OF THE INVENTION

[0005] The present invention specifically relates to the methods andapparatus for heating a catalyst bed for start-up and for providing heatto a catalyst bed during transient operation to maintain desiredreaction temperatures. Such methods and apparatus can be used in a fuelprocessor so as to make the start-up of the fuel processor faster andeasier. In fuel processors there are several catalysts that may be usedwith the present invention, including but not limited to autothermalreforming catalysts, partial oxidation catalysts, steam reformingcatalysts, water gas shift catalysts, preferential oxidation catalysts,and sulfur absorbents, as well as with anode tailgas oxidation catalystsassociated with an adjoining fuel cell.

[0006] As embodied by the present invention an electrical heatingelement may directly or indirectly heat the catalyst and thus rapidlyobtain the desired reaction temperature within the catalyst bed. Thedirect heating of catalyst is achieved by having direct contact of theheater element with the catalyst. Indirect heating is achieved by directheating of a fluid, such as a process flow, which in turn flows throughthe catalyst, thereby transferring heat to the catalyst. Additionally,indirect heating may be achieved by placing the heating element within asheath which is then either in direct contact with the catalyst or fluidwhich flows through the catalyst. As is contemplated within the scope ofthe present invention, a wide variety of catalyst forms may employ acatalyst heater including pellets, extrudates, spheres, and monoliths.In one illustrative embodiment of the present invention a catalystheater in accordance with this invention can be made of any resistivewire, cartridges, or rods that can be formed as outlined below. A powersource, such as an electric power source, provides the energy to producethe heat that preheats the catalyst bed.

[0007] One illustrative embodiment of the present invention is a reactorin a fuel processor that includes a catalyst bed, a cooling coilpositioned within the catalyst bed for removing excess heat duringnormal operation, and an electrical heating element positioned withinthe cooling coil for heating the catalyst to a desired reactiontemperature during start-up and during transient operation. Such apreferred and illustrative example is generally referred to in thepresent disclosure as sheathed heating. Important illustrativeadvantages of this illustrative embodiment include: the provision ofheat to the catalyst for fast and efficient start-up, the preheating ofthe hydrocarbon fuel feed to the fuel processor and it providesassistance to the reactor in maintaining reaction temperature duringtransient operation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The description is presented with reference to the accompanyingdrawings in which:

[0009]FIG. 1 depicts a simple process flow diagram for a fuel processor.

[0010]FIG. 2 illustrates a compact fuel processor; and

[0011]FIG. 3 illustrates one illustrative embodiment of a face heaterfor a catalyst bed.

[0012]FIG. 4 illustrates one illustrative embodiment of weaving amonolithic catalyst bed with an electrical heating element.

[0013]FIG. 5 illustrates one illustrative embodiment of wrapping amonolithic catalyst bed with an electrical heating element.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0014] The present invention is generally directed to an apparatus andmethod for heating a catalyst bed for start-up and for providing heat toa catalyst bed during transient operation to maintain desired reactiontemperatures. In a preferred aspect, the apparatus and method describedherein relate to providing heat to catalyst beds in a compact fuelprocessor for producing a hydrogen rich gas stream from a hydrocarbonfuel feed. Hydrogen rich gas produced from such compact fuel processorswill have increasing importance in the development of fuel cells,including fuel cells used to power automotive vehicles. However, otherpossible uses are contemplated for the apparatus and methods describedherein, including the start-up and reaction temperature maintenance forexothermic catalyst beds not in fuel processor service. Accordingly,while the invention is described herein as being used in conjunctionwith compact fuel processors and fuel cells, the scope of the inventionis not limited to such use.

[0015] Each of the illustrative embodiments of the present inventionrelates to exothermic catalyst beds associated with fuel processors withhydrocarbon fuel feed being directed through the fuel processor. Thehydrocarbon fuel may be liquid or gas at ambient conditions as long asit can be vaporized. As used herein the term “hydrocarbon” includesorganic compounds having C—H bonds which are capable of producinghydrogen from a partial oxidation or steam reforming reaction. Thepresence of atoms other than carbon and hydrogen in the molecularstructure of the compound is not excluded. Thus, suitable fuels for usein the method and apparatus disclosed herein include, but are notlimited to hydrocarbon fuels such as natural gas, methane, ethane,propane, butane, naphtha, gasoline, and diesel fuel, and alcohols suchas methanol, ethanol, propanol, and the like.

[0016] The fuel processor feeds include hydrocarbon fuel, oxygen, andwater. The oxygen can be in the form of air, enriched air, orsubstantially pure oxygen. The water can be introduced as a liquid orvapor. The composition percentages of the feed components are determinedby the desired operating conditions, as discussed below.

[0017] The fuel processor effluent stream includes hydrogen and carbondioxide and can also include some water, unconverted hydrocarbons,carbon monoxide, impurities (e.g. hydrogen sulfide and ammonia) andinert components (e.g., nitrogen and argon, especially if air was acomponent of the feed stream).

[0018]FIG. 1 depicts a general process flow diagram for a fuelprocessor. One of skill in the art should appreciate that a certainamount of progressive order is needed in the flow of the reactantsthrough the reactors disclosed herein.

[0019] Process step A is an autothermal reforming process in which tworeactions, partial oxidation (formula I, below) and optionally alsosteam reforming (formula II, below), are combined to convert the feedstream F into a synthesis gas containing hydrogen and carbon monoxide.Formulas I and II are exemplary reaction formulas wherein methane isconsidered as the hydrocarbon:

CH₄+½O₂→2H₂+CO   (I)

CH₄+H₂O→3H₂+CO   (II)

[0020] The partial oxidation reaction occurs very quickly to thecomplete conversion of oxygen added and produces heat. The steamreforming reaction occurs slower and consumes heat. A higherconcentration of oxygen in the feed stream favors partial oxidationwhereas a higher concentration of water vapor favors steam reforming.Therefore, the ratios of oxygen to hydrocarbon and water to hydrocarbonbecome characterizing parameters. These ratios affect the operatingtemperature and hydrogen yield.

[0021] The operating temperature of the autothermal reforming step canrange from about 550° C. to about 900° C., depending on the feedconditions and the catalyst. The invention uses a catalyst bed of apartial oxidation catalyst with or without a steam reforming catalyst.The catalyst may be in any form including pellets, spheres, extrudate,monoliths, and the like. Partial oxidation catalysts should be wellknown to those with skill in the art and are often comprised of noblemetals such as platinum, palladium, rhodium, and/or ruthenium on analumina washcoat on a monolith, extrudate, pellet or other support.Non-noble metals such as nickel or cobalt have been used. Otherwashcoats such as titania, zirconia, silica, and magnesia have beencited in the literature. Many additional materials such as lanthanum,cerium, and potassium have been cited in the literature as “promoters”that improve the performance of the partial oxidation catalyst.

[0022] Steam reforming catalysts should be known to those with skill inthe art and can include nickel with amounts of cobalt or a noble metalsuch as platinum, palladium, rhodium, ruthenium, and/or iridium. Thecatalyst can be supported, for example, on magnesia, alumina, silica,zirconia, or magnesium aluminate, singly or in combination.Alternatively, the steam reforming catalyst can include nickel,preferably supported on magnesia, alumina, silica, zirconia, ormagnesium aluminate, singly or in combination, promoted by an alkalimetal such as potassium.

[0023] Process step B is a cooling step for cooling the synthesis gasstream from process step A to a temperature of from about 200° C. toabout 600° C., preferably from about 300° C. to about 500° C., and morepreferably from about 375° C. to about 425° C., to optimize thetemperature of the synthesis gas effluent for the next step. Thiscooling may be achieved with heat sinks, heat pipes or heat exchangersdepending upon the design specifications and the need to recover/recyclethe heat content of the gas stream. One illustrative embodiment for stepB is the use of a heat exchanger utilizing feed stream F as the coolantcirculated through the heat exchanger. The heat exchanger can be of anysuitable construction known to those with skill in the art includingshell and tube, plate, spiral, etc. Alternatively, or in additionthereto, cooling step B may be accomplished by injecting additional feedcomponents such as fuel, air or water. Water is preferred because of itsability to absorb a large amount of heat as it is vaporized to steam.The amounts of added components depend upon the degree of coolingdesired and are readily determined by those with skill in the art.

[0024] Process step C is a purifying step. One of the main impurities ofthe hydrocarbon stream is sulfur, which is converted by the autothermalreforming step A to hydrogen sulfide. The processing core used inprocess step C preferably includes zinc oxide and/or other materialcapable of absorbing and converting hydrogen sulfide, and may include asupport (e.g., monolith, extrudate, pellet etc.). Desulfurization isaccomplished by converting the hydrogen sulfide to water in accordancewith the following reaction formula III:

H₂S+ZnO→H₂O+ZnS   (III)

[0025] Other impurities such as chlorides can also be removed. Thereaction is preferably carried out at a temperature of from about 300°C. to about 500° C., and more preferably from about 375° C. to about425° C. Zinc oxide is an effective hydrogen sulfide absorbent over awide range of temperatures from about 25° C. to about 700° C. andaffords great flexibility for optimizing the sequence of processingsteps by appropriate selection of operating temperature.

[0026] The effluent stream may then be sent to a mixing step D in whichwater is optionally added to the gas stream. The addition of waterlowers the temperature of the reactant stream as it vaporizes andsupplies more water for the water gas shift reaction of process step E(discussed below). The water vapor and other effluent stream componentsare mixed by being passed through a processing core of inert materialssuch as ceramic beads or other similar materials that effectively mixand/or assist in the vaporization of the water. Alternatively, anyadditional water can be introduced with feed, and the mixing step can berepositioned to provide better mixing of the oxidant gas in the COoxidation step G disclosed below.

[0027] Process step E is a water gas shift reaction that converts carbonmonoxide to carbon dioxide in accordance with formula IV:

H₂O+CO→H₂+CO₂  (IV)

[0028] This is an important step because carbon monoxide, in addition tobeing highly toxic to humans, is a poison to fuel cells. Theconcentration of carbon monoxide should preferably be lowered to a levelthat can be tolerated by fuel cells, typically below 50 ppm. Generally,the water gas shift reaction can take place at temperatures of from 150°C. to 600° C. depending on the catalyst used. Under such conditions,most of the carbon monoxide in the gas stream is converted in this step.

[0029] Low temperature shift catalysts operate at a range of from about150° C. to about 300° C. and include for example, copper oxide, orcopper supported on other transition metal oxides such as zirconia, zincsupported on transition metal oxides or refractory supports such assilica, alumina, zirconia, etc., or a noble metal such as platinum,rhenium, palladium, rhodium or gold on a suitable support such assilica, alumina, zirconia, and the like.

[0030] High temperature shift catalysts are preferably operated attemperatures ranging from about 300° C. to about 600° C. and can includetransition metal oxides such as ferric oxide or chromic oxide, andoptionally including a promoter such as copper or iron silicide. Alsoincluded, as high temperature shift catalysts are supported noble metalssuch as supported platinum, palladium and/or other platinum groupmembers.

[0031] The processing core utilized to carry out this step can include apacked bed of high temperature or low temperature shift catalyst such asdescribed above, or a combination of both high temperature and lowtemperature shift catalysts. The process should be operated at anytemperature suitable for the water gas shift reaction, preferably at atemperature of from 150° C. to about 400° C. depending on the type ofcatalyst used. Optionally, a cooling element such as a cooling coil maybe disposed in the processing core of the shift reactor to lower thereaction temperature within the packed bed of catalyst. Lowertemperatures favor the conversion of carbon monoxide to carbon dioxide.Also, a purification processing step C can be performed between high andlow shift conversions by providing separate steps for high temperatureand low temperature shift with a desulfurization module between the highand low temperature shift steps.

[0032] Process step F is a cooling step performed in one illustrativeembodiment by a heat exchanger. The heat exchanger can be of anysuitable construction including shell and tube, plate, spiral, etc.Alternatively a heat pipe or other form of heat sink may be utilized.The goal of the heat exchanger is to reduce the temperature of the gasstream to produce an effluent having a temperature preferably in therange of from about 90° C. to about 150° C.

[0033] Oxygen is added to the process in step F. The oxygen is consumedby the reactions of process step G described below. The oxygen can be inthe form of air, enriched air, or substantially pure oxygen. The heatexchanger may by design provide mixing of the air with the hydrogen richgas. Alternatively, the illustrative embodiment of process step D may beused to perform the mixing.

[0034] Process step G is an oxidation step wherein almost all of theremaining carbon monoxide in the effluent stream is converted to carbondioxide. The processing is carried out in the presence of a catalyst forthe oxidation of carbon monoxide and may be in any suitable form, suchas pellets, spheres, monolith, etc. Oxidation catalysts for carbonmonoxide are known and typically include noble metals (e.g., platinum,palladium) and/or transition metals (e.g., iron, chromium, manganese),and/or compounds of noble or transition metals, particularly oxides. Apreferred oxidation catalyst is platinum on an alumina washcoat. Thewashcoat may be applied to a monolith, extrudate, pellet or othersupport. Additional materials such as cerium or lanthanum may be addedto improve performance. Many other formulations have been cited in theliterature with some practitioners claiming superior performance fromrhodium or alumina catalysts. Ruthenium, palladium, gold, and othermaterials have been cited in the literature as being active for thisuse.

[0035] Two reactions occur in process step G: the desired oxidation ofcarbon monoxide (formula V) and the undesired oxidation of hydrogen(formula VI) as follows:

CO+½O₂→C0 ₂  (V)

H₂+½O₂→H₂O   (VI)

[0036] The preferential oxidation of carbon monoxide is favored by lowtemperatures. Since both reactions produce heat it may be advantageousto optionally include a cooling element such as a cooling coil disposedwithin the process. The operating temperature of process is preferablykept in the range of from about 90° C. to about 150° C. Process step Gpreferably reduces the carbon monoxide level to less than 50 ppm, whichis a suitable level for use in fuel cells, but one of skill in the artshould appreciate that the present invention can be adapted to produce ahydrogen rich product with of higher and lower levels of carbonmonoxide.

[0037] The effluent exiting the fuel processor is a hydrogen rich gascontaining carbon dioxide and other constituents which may be presentsuch as water, inert components (e.g., nitrogen, argon), residualhydrocarbon, etc. Product gas may be used as the feed for a fuel cell orfor other applications where a hydrogen rich feed stream is desired.Optionally, product gas may be sent on to further processing, forexample, to remove the carbon dioxide, water or other components.

[0038] In one illustrative embodiment of a fuel processor, a compactfuel processor is of modular construction with individual modular units,which are separable, rearrangeable, and individually replaceable.Referring to FIG. 2, the compact fuel processor 100 includes a series ofindividual modules (110, 120, 130, 140, 150, 160 and 170). The modularunits may be used in any orientation, e.g., vertical or horizontalorientation, and is adapted to be used in conjunction with a fuel cellsuch that the hydrogen rich product gas of the reactor described hereinis supplied directly to a fuel cell as a feed stream. While the modulescan have any cross sectional configuration, such as circular,rectangular, triangular, etc., a circular cross section is preferredwith the fuel processor 100 being of a generally tubular shape.

[0039] Fuel processor 100 as shown in FIG. 2 effects the processdiagrammatically illustrated in FIG. 1. Feed stream F is introducedthrough inlet pipe 102 and product gas P is drawn off via outlet pipe103. The apparatus 100 includes several modules that may be stacked toform a modular assembly that can be modified by the replacement ofindividual modules. Each module performs a separate operational functionand is generally configured as shown in FIG. 2. Module 110 is theautothermal reforming module corresponding to process step A of FIG. 1.Module 120 is a cooling step corresponding to process step B of FIG. 1.In this illustrative embodiment, heat exchanger 121 is shown as ageneral heat sink for Module 120. Module 130 is a purifying modulecorresponding to process step C of FIG. 1. Module 140 is an optionalmixing step corresponding to process step D of FIG. 1. Feed nozzle 131provides an optional water stream feed to Module 140 to aid in drivingthe water gas shift reaction (Equation IV) of Module 150. Module 150 isa water gas shift module corresponding to process step E of FIG. 1. Feednozzle 151 provides a source for oxygen to process gas for the oxidationreaction (Equation V) of Module 170. Module 150 also contains a heatexchanger (not shown) positioned within or surrounding the catalyst bedso as to maintain a desired water gas shift reaction temperature. Module160 is a cooling step corresponding to process step F of FIG. 1. In thisillustrative embodiment, heat exchanger 161 is shown as a general heatsink for Module 160. Module 170 is an oxidation step corresponding toprocess step G of FIG. 1. Module 170 also contains a heat exchanger (notshown) positioned within or surrounding the catalyst bed so as tomaintain a desired oxidation reaction temperature. One of skill in theart should appreciate that the process configuration described in thisillustrative embodiment may vary depending on numerous factors,including but not limited to feedstock quality and required productquality.

[0040] The present invention specifically relates to the methods andapparatus for heating a catalyst bed for start-up and for providing heatto a catalyst bed during transient operation to maintain desiredreaction temperatures. Transient operation includes but is not limitedto hydrocarbon fuel feedstock changes to the fuel processor, processupsets, changes in catalyst activity, and increased or decreasedvolumetric throughput of feed to the fuel processor. In fuel processorssuch as the ones described above, there are several catalysts that maybe used with the present invention, including autothermal reformingcatalysts, partial oxidation catalysts, steam reforming catalysts, watergas shift catalysts, preferential oxidation catalysts, and sulfurabsorbents. In these exothermic catalyst beds, heating the catalyst toreaction temperature is important for efficiently starting-up a fuelprocessor from a cold start. Because one envisioned use for compact fuelprocessors is in automotive vehicles, a solution utilizing electricalheating elements is desirable. Furthermore, transient operation is animportant issue for ensuring stable hydrogen rich gas supply for a fuelcell that is fed directly from a fuel processor.

[0041] In general, an electrical heating element may directly orindirectly heat the catalyst. The direct heating of catalyst is achievedby having direct contact of the heater element with the catalyst.Indirect heating is achieved by direct heating of a fluid, such as aprocess flow, which in turn flows through the catalyst, therebytransferring heat to the catalyst. Additionally, indirect heating may beachieved by placing the heating element within a sheath which is theneither in direct contact with the catalyst or fluid which flows throughthe catalyst. By these means, catalyst of many forms may employ thiscatalyst heater including pellets, extrudates, spheres, and monoliths.The catalyst heater in accordance with this invention can be made of anyresistive wire, cartridges or rods that can be formed as outlined below.A power source, such as an electric power source, provides the energy toproduce the heat.

[0042] Referring now to FIG. 3, face heater 300 can be utilized toprovide heat to a catalyst bed face 310. The catalyst bed face isrepresented in this illustrative embodiment as one end of acylindrically shaped catalyst bed. It will be appreciated by one ofskill in the art that the orientation of the catalyst bed may either bevertical or horizontal in the present invention. In this illustrativeembodiment, face heater 300 is an electrical heating element formed in aspiral design along the face of the catalyst bed, although otherillustrative embodiments may be utilized to provide sufficient heattransfer to the catalyst bed face. By passing a small flow of reactantsthrough the electrical heating element and catalyst bed, the exothermicreaction is initiated at the face of the catalyst bed. The heat providedby the face heater diffuses through the volume of the catalyst bed andadditionally the heat of reaction produced at the catalyst bed facepropagates throughout the catalyst bed thereby heating the catalyst bedfor start-up. A preferred aspect of this illustrative embodiment is theuse of the face heater 300 on the upstream face of the catalyst bed(i.e. the face of the catalyst bed that sees the reactor feed) such thatthe heat of reaction is carried into the “cold” catalyst to improvestart-up efficiency of the catalyst.

[0043] Referring now to FIG. 4, the electrical heating element 400 iswoven through the catalyst bed 410. In this illustrative embodiment, theelectrical heating element is woven through either a catalyst bed ofpellets, extrudates, spheres, etc., or through a monolithic catalyststructure. The weaving design (such as a coil) may be designed foroptimal heating of the catalyst bed. This illustrative embodimentprovides heating from the inside of the catalyst outwards. The flowing afluid through the catalyst during heating is optional.

[0044] Referring now to FIG. 5, the electrical heating element 500 iswrapped around a monolithic catalyst structure 510. This providesheating from the outside of the catalyst towards the center. The flowinga fluid through the catalyst during heating is optional.

[0045] Another illustrative embodiment includes a reactor in a fuelprocessor that includes a catalyst bed, a cooling coil positioned withinthe catalyst bed for removing excess heat during normal operation, andan electrical heating element positioned within the cooling coil forheating the catalyst to a desired reaction temperature during start-upand during transient operation. This is an example of sheathed heatingas described above. One of skill in the art should appreciate that manyadvantages of this illustrative embodiment are that it provides heat tothe catalyst for fast and efficient start-up, it preheats thehydrocarbon fuel feed to the fuel processor which may pass through thecooling coil in a compact fuel processor design, and it assists thereactor in maintaining reaction temperature during transient operation.

[0046] While the apparatus, compositions and methods of this inventionhave been described in terms of preferred or illustrative embodiments,it will be apparent to those of skill in the art that variations may beapplied to the process described herein without departing from theconcept and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the scope and concept of the invention as it is set out in thefollowing claims.

What is claimed is:
 1. A method for heating a catalyst bed for start-up,comprising: providing a catalyst bed having an upstream face and adownstream face; providing an electrical heating element positionedalong one face of the catalyst bed; passing a small flow of reactantsthrough the electrical heating element and catalyst bed; and heating theelectrical heating element to initiate an exothermic reaction at theface of the catalyst bed, wherein the heat of reaction propagatesthroughout the catalyst bed thereby heating the catalyst bed forstart-up.
 2. The method of claim 1, wherein the electrical heatingelement is positioned along the upstream face of the catalyst bed. 3.The method of claim 1, wherein the electrical heating element is formedin a spiral design along one face of the catalyst bed.
 4. The method ofclaim 1, wherein the catalyst bed is selected from the group consistingof pellets, extrudates, spheres, monoliths, and any combinationsthereof.
 5. The method of claim 1, wherein the catalyst bed containscatalyst selected from the group consisting of autothermal reformingcatalysts, partial oxidation catalysts, steam reforming catalysts, watergas shift catalysts, preferential oxidation catalysts, anode tailgasoxidation catalysts, and sulfur absorbents.
 6. A reactor module for usein a compact fuel processor, comprising: a catalyst bed having anupstream face and a downstream face; and an electrical heating elementpositioned along the upstream face of the catalyst bed, the heatingelement capable of initiating an exothermic reaction at the upstreamface of the catalyst bed in the presence of a small flow of reactants.7. The reactor module of claim 6, wherein the electrical heating elementis formed in a spiral design.
 8. The reactor module of claim 6, whereinthe catalyst bed is selected from the group consisting of pellets,extrudates, spheres, monoliths, and any combinations thereof.
 9. Thereactor module of claim 6, wherein the catalyst bed contains catalystselected from the group consisting of autothermal reforming catalysts,partial oxidation catalysts, steam reforming catalysts, water gas shiftcatalysts, preferential oxidation catalysts, anode tailgas oxidationcatalysts, and sulfir absorbents.
 10. A reactor module for use in acompact fuel processor, comprising: a catalyst bed; a cooling coilpositioned substantially within the catalyst bed for removing excessheat during normal operation; and an electrical heating elementpositioned within the cooling coil, the heating element capable ofheating the catalyst to a desired reaction temperature.
 11. The reactormodule of claim 10, wherein the catalyst bed is selected from the groupconsisting of pellets, extrudates, spheres, monoliths, and anycombinations thereof.
 12. The reactor module of claim 10, wherein thecatalyst bed contains catalyst selected from the group consisting ofautothermal reforming catalysts, partial oxidation catalysts, steamreforming catalysts, water gas shift catalysts, preferential oxidationcatalysts, anode tailgas oxidation catalysts, and sulfur absorbents. 13.A method for heating a catalyst bed, comprising: providing an electricalheating element positioned within a cooling coil located substantiallywithin the catalyst bed; and heating the electrical heating elementthereby heating the catalyst bed to a desired temperature.
 14. Themethod of claim 13, wherein the desired temperature is the start-uptemperature.
 15. The method of claim 13, wherein the desired temperatureis the desired reaction temperature during transient operation.
 16. Amethod for heating a catalyst bed to a desired temperature, comprising:providing a catalyst bed in communication with an electrical heatingelement; and heating the electrical heating element so as to maintainthe desired temperature of the catalyst bed.
 17. The method of claim 16,wherein the desired temperature is the start-up temperature.
 18. Themethod of claim 16, wherein the desired temperature is the desiredreaction temperature during transient operation.
 19. The method of claim16, wherein the electrical heating element is weaved through thecatalyst bed.
 20. The method of claim 16, wherein the catalyst bed is amonolith.
 21. The method of claim 18, wherein the electrical heatingelement is wrapped around the monolith.
 22. A method for heating acatalyst bed to a desired temperature, comprising: positioning anelectrical heating element upstream of the catalyst bed; and passing afluid across the electrical heating element and through the catalystbed, wherein the catalyst bed is heated to the desired temperature. 23.The method of claim 22, wherein the desired temperature is the start-uptemperature.
 24. The method of claim 22, wherein the desired temperatureis the desired reaction temperature during transient operation.